Which of the following best describes the principles of biomechanics?

The principles of biomechanics primarily focus on the analysis of mechanical aspects related to forces and motion as they pertain to human movement. This field examines how the body moves and interacts with the environment through concepts such as kinetics (the study of forces) and kinematics (the study of motion without regard to forces). By understanding these principles, athletes and coaches can optimize performance, reduce the risk of injury, and enhance training methods.

The focus on energy systems, psychological factors, and nutritional needs, while important in sports science, does not encapsulate what biomechanics is fundamentally about. These areas may intersect with biomechanics in understanding performance, but they do not describe the core principles that govern movement mechanics. Thus, option B precisely captures the essence of biomechanics in describing the interactions of forces and motions in human activity.